Though Tammy Dahlgren grew up hooked on puzzles, computing wasn’t always such a clear path for her. The first time she was exposed to computers was in college, when she realized programming is just another type of puzzle to solve.

Tammy learned about LLNL at a recruiting event while working evenings and weekends toward a master’s degree in computer science at California State University, Sacramento—where she was often the only woman in her courses. In the more than 30 years since arriving at the Lab, she has become involved in the annual Grace Hopper Celebration of Women in Computing (GHC) conference, the world’s largest conference for women and non-binary technologists.

“The first time I attended the conference and saw the large facility full of women, it was just amazing,” Tammy says. “After being in the field for as long as I have, often the only woman in a class or on a project, it’s inspiring to see the surge in women choosing a technical career path.”

Tammy’s involvement with GHC started in 2015, when she served as a committee member on the Software Engineering track. From 2016 through 2023, she served as a co-chair on technical track committees, including the Software Engineering, Computer Systems Engineering, and Product Management tracks. During this time, the event doubled in size from about 15,000 attendees during her first year as a co-chair to 30,000 in 2022, with representation from nearly 80 countries.

Tammy has experienced a lot of change in her three decades at the Lab. She’s worked on a diverse variety of projects, including supervisory control systems for the National Ignition Facility, animal disease modeling, mass hierarchical storage systems, RADIUSS, and more. She also completed her doctorate at UC Davis through the Lab’s UC Davis Distance Learning Program. Since 2019, Tammy has worked on Spack (Supercomputing PACKage manager), which is an open-source project for automating the build and installation of high performance computing (HPC) software. Spack is now a standard tool for package deployment in the Department of Energy’s Exascale Computing Project.

“While working on my PhD, I enjoyed the opportunities to write papers and give presentations,” recalls Tammy. “Similarly, Spack not only allows me to do the technical work I love, but I’m also able to give presentations and tutorials.”

Spack has over a thousand contributors and is used at top supercomputing facilities worldwide. “It’s exciting to be a part of such a large open-source endeavor,” she notes. “I was initially the only woman on the core development team when I joined. Now we have another, somewhat recent graduate, who I enjoy mentoring.”

Tammy’s career and educational accomplishments also inspired her daughter to pursue graduate studies in computer science and volunteer as a GHC committee member. After working at a Silicon Valley startup, her daughter is now a software engineer at Hewlett Packard Enterprise.

Mentoring and outreach are important to Tammy. In addition to working with AnitaB.org on GHC, she has recently co-organized two Computing Summer Hackathons, mentored for the Girls Who Code—Big program, and volunteered for a local high school computer science rally. Beyond outreach, Tammy also cares deeply about Lab life in general. In 2022, she participated in the Return to New Normal focus group, which helped the workforce adapt to a hybrid work environment, and is currently part of the Employee Experience and Lab in the Know (LINK) communications focus groups.

When she’s not programming, inspiring other women to pursue careers in technology, and improving life at the Lab, Tammy can be found working in her new garden. With an eye toward conservation and the health of the local ecosystem, she has been learning about heat-tolerant, drought-resistant, and native plants. The crepe myrtles she planted last year are doing especially well.

—Anashe Bandari